1. Field of the Invention
This invention relates generally to the field of two-way portable transceivers having removable antenna structures and an arrangement for protecting the transmitter from an improper antenna. More particularly, this invention relates to the field of two-way portable transceivers incorporating integral battery pack/antennas and an arrangement for warning the user or taking protective action if an inappropriate battery pack/antenna is attached to his transceiver.
2. Background
In a copending U.S. patent application, entitled "Low Profile Antenna Suitable for Use With Two-Way Portable Transceivers", to Stelios Patsiokas and Oscar Garay, Ser. No. 06/596,800 and assigned to Motorola, Inc., the assignee of the present invention, filed of common data herewith, an antenna structure suitable for use inside the battery enclosure of a two-way portable transceiver is described and claimed. This copending patent application is hereby incorporated by reference and made a part of this document as if disclosed fully herein.
The use of antenna structures disposed within the battery pack enhances the appearance and size of two-way portable transceivers and under certain conditions may even improve radiation efficiency over conventional top mounted whip, helical or dipole antennas. However, by placing the antenna within the battery enclosure, the likelihood of installation of an inappropriate battery pack/antenna increases since the battery pack is a frequently removed and installed item. This could result in poor performance or inadvertent damage to the radio transmitter by using an antenna designed to operate in a completely different band.
This problem could, of course, be solved by creating a different mechanical coupling arrangement between the transceiver and the battery pack/antenna for each frequency band or each antenna requirement. While this is an effective solution, it requires that a number of different transceiver and battery enclosures be tooled, designed manufactured and stocked. This could result in a prohibitively expensive mechanism for preventing such problems.
In more conventional top mounted antenna arrangements for two-way portable transceivers, the likelihood of installation of an inappropriate antenna is low due to the frequent use of differing antenna connectors for various frequency bands. Also, since the antenna structure itself is visable to the user, its physical size and appearance serve to indicate to the user that he has his usual antenna attached. However, it is unusual for the user of a transceiver having conventional top mounted antenna structures to have need to remove the antenna. This is only likely to occur during service, testing or installation of some form of power boosting accessory.
Such is not the case for the user of a transceiver having a battery pack/antenna. When the battery cells are depleted, it is frequently the case that the user will substitute a spare while the original battery pack is charging. Some users prefer to use disposable primary cells in lieu of charging rechargable cells. These users are frequent purchasers of new battery packs (and thus antennas) and the inadvertent purchase of an inappropriate battery pack/antenna could clearly result in unexplainable poor performance, reduced transmitter and receiver range or even damage to the transmitter.
Thus, it is desirable to provide the user with an indication that the battery pack/antenna is inappropriate if this is the case. If the transmitter is susceptible to damage from an improper load, it may also be desirable to inhibit transmitter operation in the event an inappropriate antenna is attached or at least modify the transmitter operation by reducing the power output to the antenna or reducing the allowable transmit time.